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  <title>Decrease a stored number</title>
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  <div id="layout-content"><div id="function.apc-dec" class="refentry">
 <div class="refnamediv">
  <h1 class="refname">apc_dec</h1>
  <p class="verinfo">(PECL apc &gt;= 3.1.1)</p><p class="refpurpose"><span class="refname">apc_dec</span> &mdash; <span class="dc-title">Decrease a stored number</span></p>

 </div>

 <div class="refsect1 description" id="refsect1-function.apc-dec-description">
  <h3 class="title">说明</h3>
  <div class="methodsynopsis dc-description">
   <span class="methodname"><strong>apc_dec</strong></span>
    ( <span class="methodparam"><span class="type">string</span> <code class="parameter">$key</code></span>
   [, <span class="methodparam"><span class="type">int</span> <code class="parameter">$step</code><span class="initializer"> = 1</span></span>
   [, <span class="methodparam"><span class="type">bool</span> <code class="parameter reference">&$success</code></span>
  ]] ) : <span class="type">int</span></div>

  <p class="para rdfs-comment">
   Decreases a stored integer value.
  </p>
 </div>


 <div class="refsect1 parameters" id="refsect1-function.apc-dec-parameters">
  <h3 class="title">参数</h3>
  <dl>

   
    <dt>
<code class="parameter">key</code></dt>

    <dd>

     <p class="para">
      The key of the value being decreased.
     </p>
    </dd>

   
   
    <dt>
<code class="parameter">step</code></dt>

    <dd>

     <p class="para">
      The step, or value to decrease.
     </p>
    </dd>

   
   
    <dt>
<code class="parameter">success</code></dt>

    <dd>

     <p class="para">
      Optionally pass the success or fail boolean value to
      this referenced variable.
     </p>
    </dd>

   
  </dl>

 </div>


 <div class="refsect1 returnvalues" id="refsect1-function.apc-dec-returnvalues">
  <h3 class="title">返回值</h3>
  <p class="para">
   Returns the current value of <code class="parameter">key</code>&#039;s value on success,
    或者在失败时返回 <strong><code>FALSE</code></strong>
  </p>
 </div>


 <div class="refsect1 examples" id="refsect1-function.apc-dec-examples">
  <h3 class="title">范例</h3>
  <div class="example" id="example-402">
   <p><strong>Example #1 <span class="function"><strong>apc_dec()</strong></span> example</strong></p>
   <div class="example-contents">
<div class="phpcode"><pre><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br /></span><span style="color: #007700">echo&nbsp;</span><span style="color: #DD0000">"Let's&nbsp;do&nbsp;something&nbsp;with&nbsp;success"</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">PHP_EOL</span><span style="color: #007700">;<br /><br /></span><span style="color: #0000BB">apc_store</span><span style="color: #007700">(</span><span style="color: #DD0000">'anumber'</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">42</span><span style="color: #007700">);<br /><br />echo&nbsp;</span><span style="color: #0000BB">apc_fetch</span><span style="color: #007700">(</span><span style="color: #DD0000">'anumber'</span><span style="color: #007700">),&nbsp;</span><span style="color: #0000BB">PHP_EOL</span><span style="color: #007700">;<br /><br />echo&nbsp;</span><span style="color: #0000BB">apc_dec</span><span style="color: #007700">(</span><span style="color: #DD0000">'anumber'</span><span style="color: #007700">),&nbsp;</span><span style="color: #0000BB">PHP_EOL</span><span style="color: #007700">;<br />echo&nbsp;</span><span style="color: #0000BB">apc_dec</span><span style="color: #007700">(</span><span style="color: #DD0000">'anumber'</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">10</span><span style="color: #007700">),&nbsp;</span><span style="color: #0000BB">PHP_EOL</span><span style="color: #007700">;<br />echo&nbsp;</span><span style="color: #0000BB">apc_dec</span><span style="color: #007700">(</span><span style="color: #DD0000">'anumber'</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">10</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$success</span><span style="color: #007700">),&nbsp;</span><span style="color: #0000BB">PHP_EOL</span><span style="color: #007700">;<br /><br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">$success</span><span style="color: #007700">);<br /><br />echo&nbsp;</span><span style="color: #DD0000">"Now,&nbsp;let's&nbsp;fail"</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">PHP_EOL</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">PHP_EOL</span><span style="color: #007700">;<br /><br /></span><span style="color: #0000BB">apc_store</span><span style="color: #007700">(</span><span style="color: #DD0000">'astring'</span><span style="color: #007700">,&nbsp;</span><span style="color: #DD0000">'foo'</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">$ret&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">apc_dec</span><span style="color: #007700">(</span><span style="color: #DD0000">'astring'</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">1</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$fail</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">$ret</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">var_dump</span><span style="color: #007700">(</span><span style="color: #0000BB">$fail</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</pre></div>
   </div>

   <div class="example-contents"><p>以上例程的输出类似于：</p></div>
   <div class="example-contents screen">
<div class="cdata"><pre>
Let&#039;s do something with success
42
41
31
21
bool(true)

Now, let&#039;s fail
bool(false)
bool(false)
</pre></div>
   </div>
  </div>
 </div>



 <div class="refsect1 seealso" id="refsect1-function.apc-dec-seealso">
  <h3 class="title">参见</h3>
  <ul class="simplelist">
   <li class="member"><span class="function"><a href="apc_inc.html" class="function" rel="rdfs-seeAlso">apc_inc()</a> - 递增一个储存的数字</span></li>
  </ul>
 </div>


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